Control.Distributed.Process.Task.Queue.BlockingQueue

A simple bounded (size) task queue, which accepts requests and blocks the sender until they're completed. The size limit is applied to the number of concurrent tasks that are allowed to execute - if the limit is 3, then the first three tasks will be executed immediately, but further tasks will then be queued (internally) until one or more tasks completes and the number of active/running tasks falls within the concurrency limit.

Note that the process calling executeTask will be blocked for _at least_ the duration of the task itself, regardless of whether or not the queue has reached its concurrency limit. This provides a simple means to prevent work from being submitted faster than the server can handle, at the expense of flexible scheduling.

Documentation

data BlockingQueue a

type SizeLimit = Int

Limit for the number of concurrent tasks.

data BlockingQueueStats

Constructors

BlockingQueueStats

Fields

maxJobs :: Int

activeJobs :: Int

queuedJobs :: Int

Instances

Generic BlockingQueueStats

Binary BlockingQueueStats

type Rep BlockingQueueStats

start :: forall a. Serializable a => Process (InitResult (BlockingQueue a)) -> Process ()

Start a queue with an upper bound on the # of concurrent tasks.

pool :: forall a. Serializable a => SizeLimit -> Process (InitResult (BlockingQueue a))

Define a pool of a given size.

executeTask :: forall s a. (Addressable s, Serializable a) => s -> Closure (Process a) -> Process (Either ExitReason a)

Enqueue a task in the pool and block until it is complete.

stats :: forall s. Addressable s => s -> Process (Maybe BlockingQueueStats)

Fetch statistics for a queue.